I have seen some people magnetize just about everything, but I personally don't think there is a point to it. You never really swap out weapons, so all you're getting is being able to point up or down more, decreased stability, and I guess less chance of an arm breaking off. I used to play Tau in 40k, there I would magnetize almost everything. Here, not really needed.

Personally, I'm just magnetizing to fit everything on dropships, Cruise/skyhammer/missile options on Tritons and Athenas, and probably also the tail weapon on a Hades. Maybe the Missile rack on the Taranis if I ever get some.

I have magnetized all the walkers so they can be mounted on the dropships (that are magnetized too of course).

I didn't magnetized the janus/mercury/tritons because I don't have magnets of the right size. I also glued the guns/missiles on the tritons because I am too affraid of loosing a part of that size...

Hades tail magnetized for transport and posing. It is not as difficult as it seems.

All the APCs, taranises and grav tank are magnetized also, for mounting on dropship and turret positioning.

Overall, I don't think it is really necessary, as it is not very practical to use a dropship with walkers attached in game (the heavier walkers just fall most of the time when the dropship is handled for movement). Also, an issue some people have reported is that the walkers are then often sticking to the metal ruler (but it didn't happend to me).

I'm magetizing all my vehicals/walkers/dropships so they can be carried (looks cool + PHR is the easit to do, try UCM) + one Zues, because when I'm I going to use 2 zueses. I plan on using the extra mechit arms from the platic starter with some 40k bitz. That way I can run a odin or hyperion or enyo w/ my comander.

I like magnets. I magnetized the dropship slots for all my dropships and the vehicles so they can link up. I originally used 2 mm magnets for the Dropships, but with the new metal legs, I had to switch to 3mm for enough strength. I never thought of using screws, would have saved alot of time with checking and double checking polarity.

In addition to that, I went a little overboard:The primary engines on all my Neptunes and Poseiden All the optional weapons for my Tritons(I tried to magnetize the troop compartment, but couldn't get it to work right so I abandoned the idea and glued it on).The torsos all my walkers.The turrets on my Junos and Angelos.The Hades tail(this one is justified since I wanted it to look combat ready when deployed while still be able to carry it in a dropship).

I considered doing the arms, but decided not to cross that line. I will do after I decide to make my Angelos Jetskimmers hover.

With the PHR starter yes as it includes the bits to swap the weapons to field either variant of the 3 standard mechs along with the extra turrets for the APC. Other than those and the dropships not really since everything from the blisters includes only the essential parts anyways.